That barrier is in the genetic information of the animal. You can breed every known type of rabbit from now till eternity, and you'll never get anything but a rabbit, and certainly nothing like a horse or a dog. Other than that, you and I agree 100%.
Thank you for providing yet another example of the absurdity that is the Creationists' definition of "macro-evolution."
Of course you won't get anything like a horse or a dog. The populations that produced those genes split off from the populations that produced rabbit genes generations ago, and the gene pools today are different.
But, if something kills off all the dogs, without destroying the environments that dogs are adapted for, a population of a different animal -- probably not rabbits, but wolverines would not be a bad choice -- would adapt to fill the missing ecological niche, eventually separating from the mother population and producing a new species.
Kangaroos are not deer, but they evolved to fill the same niche in Australia, where the placental mammals never colonized until brought there by Man.
I don't follow...how is our use of the same word co-opting it? Like I said, when it comes to Micro, only a blithering idiot would say it doesn't happen. But like I said, you can't get from one cell that magicked its way into existence to everything else alive today.
During the brief time that they used the words "micro-evolution" and "macro-evolution," evolutionary scientists simply used them as shorthand to discuss small variations within species and large variations at higher taxonomic levels. It was understood that these larger variations were simply accumlations of smaller ones collected over large periods of time. Neither word had any limiting meaning on the evolutionary model.
When Creationists started using the same words to mean something else (First "micro-" meant "within species evolution, which can't be denied," and "macro-" meant "speciation which we don't believe happens," and later, after speciation was demonstrated, "all evolution which cannot be denied," and "any evolution I don't want to believe in"), the evolutionary scientists stopped using the words altogether. That's what I mean by the words were co-opted by the Creationists.
